This white paper marks the first public effort by glaciologists to evaluate potential technological interventions that might address catastrophic sea-level rise scenarios.
Although it does not endorse specific interventions, it calls for a "major initiative" over the next decades to research which, if any, interventions could and should be utilized.
"Everyone who is a scientist hopes that we don't have to do this research," said Douglas MacAyeal, a professor of geophysical sciences with the University of Chicago who has studied glaciers for nearly 50 years and is a co-author on the white paper. "But we also know that if we don't think about it, we could be missing an opportunity to help the world in the future."
The paper is the result of two recent conferences at the University of Chicago and Stanford University on geoengineering, encouraged by the newly formed Climate Systems Engineering initiative at UChicago. This initiative aims to understand the benefits, risks, and governance of technologies that might reduce the impacts of accumulated greenhouse gases.
Tipping Points
Scientists have documented major changes in every significant glacier system worldwide. As climate change continues, these massive ice sheets will release more water, leading to rising global sea levels. The oceans have already risen by 8 to 9 inches since the late 1800s.
Most of the ice affecting global sea levels is concentrated in a few areas in the Arctic and Antarctic. This has prompted speculation about whether it would be possible to slow or halt this melting, such as by installing barriers around ice sheets to insulate them from warming ocean water.
However, any such intervention could have major consequences, from high costs with little effect to significantly disturbing Arctic ecosystems and livelihoods. Many questions must be answered before any such effort could be undertaken.
"It will take 15 to 30 years for us to understand enough to recommend or rule out any of these interventions," said co-author John Moore, a professor with the Arctic Center at the University of Lapland.
"Our argument is that we should start funding this research now, so that we aren't making panicked decisions down the road when the water is already lapping at our ankles," said MacAyeal.
The report emphasizes that the primary task is to stop emitting carbon into the atmosphere. "We can never say often enough that that is the first priority," said Moore.
But it is also possible that ice sheets have a tipping point for collapsing-and that we may have already passed it.
"Humans have already released so much carbon dioxide that we are seeing profound changes in every glacier system around the world," said MacAyeal. "Many of these are likely to have a tipping point where even if we were to stop emitting all carbon worldwide tomorrow, the system would still collapse. And we are not in a position now to say that we haven't already crossed those points."
Types of Interventions
The two conferences, one held at the University of Chicago last October and the other at Stanford University in December, brought together dozens of glaciologists, engineers, and experts from related fields.
Participants summarized current knowledge of glacier science and discussed two major categories of proposed glacier interventions.
The first category involves constructing berms or fiber-based "curtains" moored on the seabed around the feet of ice shelves to prevent warm water from undermining them. (The biggest threat to ice sheets is warmer ocean water rather than hotter air temperatures.)
"From preliminary studies, the actual engineering required might be smaller than you might think," said MacAyeal. "For example, the Thwaites Glacier in Antarctica might require as little as 50 miles of seabed nets and curtains to make a difference."
The second category of intervention aims to slow the flow of streams carrying meltwater off the ice sheets. As an ice sheet melts, streams form and carry that melting water to the sea; the hypothesis is that reducing this water flow would cause the ice stream to freeze up and halt melting. One way to reduce the flow might be to drill holes down to the glacier bed-to either drain water from below the ice before it affects the glacier or to try to artificially freeze the glacier bed.
Both benefits and drawbacks remain unclear for both approaches. It's possible that seawalls could simply deflect warm water to nearby ice shelves; the installation could also disrupt local sea life and the lives of nearby residents. Meanwhile, the drilling approach might be less harmful to ecosystems but might also be less effective and would require extensive engineering under harsh conditions.
The report also emphasizes that any interventions would need to involve global participation, not just the wealthiest nations. It calls for "robust participation of sociologists, humanists, ecologists, community leaders, scientific and engineering governing bodies, international treaty organizations, and other relevant stakeholders in guiding the research."
Testing these approaches is most likely to be done in the Arctic, which is much easier to access than the Antarctic. However, thousands of people, including many Indigenous peoples, live in and depend on the Arctic. "It is imperative that any of these interventions be done in concert with these voices," Moore said.
Vigorous Debate
The report identifies major areas of future research, including understanding natural processes that might limit ice sheet deterioration, human interventions that could enhance these processes, and the window of opportunity for implementing interventions.
The group calls for a major initiative to conduct a "vigorous debate" on the ethical, social justice, and governance issues surrounding glacial interventions, recommend areas of immediate research need, and engage local and international stakeholders.
"We want to give future generations as much glaciological knowledge as possible in case they need it," said MacAyeal.
Research Report:Glacial Climate Intervention: A Research Vision
Related Links
University of Chicago
Beyond the Ice Age
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